• [convert] javascript high performance array de duplication


    Original address: https://www.cnblogs.com/wisewrong/p/9642264.html   I. test template Array de duplication is a commonplace problem. There are various solutions on the Internet In order to test the performance of these solutions, I wrote a test template to calculate the time-consuming of array de duplication // distinct.js let arr1 = Array.from(new Array(100000), (x, index)=>{ return index }) […]

  • Injection and utilization of database system functions


    Database system functions MySQL system functions *More functions: https://blog.csdn.net/qq646040754/article/details/82721801 Mathematical functions: bin(x)/hex(x)Returns the binary / hexadecimal encoding of X abs(x)Absolute value of X mod(x,y)Yu Yunsuan sqrt(x)Square root operation ceil(x) / ceiling(x) rand()Returns a floating-point number between 0 and 1 round(x,D)Round to retain D decimal places sign(x)Returns the symbol of X pow(x,y)The Y power of X […]

  • KMP template


    There are too many pictures in the string, so in order to save my notes, blogging is the best way 1. KMP template (from caioj, but it can’t be registered now, so I’ll put the topic up) 1177: [Video] KMP template: whether the substring appears (meta problem by scy) Time limit: 1 secMemory limit: 256 […]

  • [react practice summary] input value of form immediate verification (based on antd design)


    1. Judge the length of input value 1.1 limit the length of input value according to the type of input value At this time, you need to use the custom verification rules. If the length is required: 5 characters for Chinese input, 10 characters for non Chinese input {getFieldDecorator(‘name’, { rules: [ { required: true, […]

  • What character does TERM use in [20190910] index branching block. TXT


    What character does TERM use in [20190910] index branching block. TXT // Do index block dump, some root, branch node TERM, never pay attention to the use of character representation, a simple look. 1. Environment:[email protected]> @ ver1 PORT_STRING                    VERSION        BANNER                                                                               CON_ID—————————— ————– ——————————————————————————– ———-IBMPC/WIN_NT64-9.1.0      Oracle Database 12c Enterprise Edition Release – 64bit Production              […]

  • Sequential Storage Structure of Linear Table of Data Structure in C Language


    Linear table, or linear storage structure, stores data with “one-to-one” relationship “linearly” into physical space. This storage structure is called linear storage structure, referred to as linear table. Note: Data stored in linear tables must be of the same type. The data stored in linear tables are either not all shaping or all strings. One […]

  • JAVA-Base-Array


    I. Array Concept Arrays are containers with fixed length and variable content that store multiple data of the same type.   2. Defining arrays Method 1:        The array defined in this way only defines the length without specifying the initial value, then the initial value adopts the default value. The numerical type is 0, […]

  • Introduction to the usage of length, length hb, substr and substrb functions in Oracle


    I remember that I made such a mistake when I developed form. For a field in form, it corresponds to a field in a table in the database, assuming that the field in the database is usually 20 Chinese characters in length. Later, when I developed form, when I set the length of item type, […]

  • Explanation of functions and uses in arrays


    1. var arr = [ ];    Array: []Empty array console.logbyArray(0)    Function: DefinitionAn empty array is used to receive 2. var str = ’ ’  Empty string Function: Define empty strings to receive 3. arr [arr. length] = Add to the last array Arr. push (‘add’) – –Commonly used 4. arr. splice (0, 1); delete one bit […]

  • 06, MySQL – Column Type


    1. Integer type I. Signed Integers (1) TinyintSingle byte shaping, the system uses a byte to save the shaping: a byte = 8 bits, the maximum value can be expressed is 0-255. (2) SmallintDouble-byte shaping, the system uses two bytes to save shaping: can represent between 0-65535 (3) MediumintThree bytes shaping, using three bytes to […]

  • 08, MySQL – String Type


    String type 1、Char Fixed-length characterAfter specifying the length, the system must allocate the specified space for storing data Basic grammar: Char (L), L stands for the number of characters (Chinese is the same as English letters), and L is 0 to 255 in length. 2、Varchar Variable length characterAfter specifying the length, the system calculates the […]